25,000 recipients at 1,500 emails/day.
Know exactly how much email your SMTP setup can send.
Calculate realistic operational capacity from your SMTP accounts, account limits, sending delay, active hours and campaign size.
SMTP sending setup
Enter the limits you actually intend to use. The calculator uses the lower of the daily limit and delay-based capacity.
Based on your selected start date.
To complete within 7 days.
Above your current 5 accounts.
Capacity breakdown
See which setting is actually limiting throughput.
Scaling comparison
See how additional SMTP accounts change completion time.
| Accounts | Emails/day | Campaign |
|---|
Operational summary
This is a throughput calculator, not a deliverability guarantee.
How the calculation works
The tool first calculates how many messages each SMTP account could send from your delay and active hours. It then compares that number with your daily per-account limit and uses whichever is lower. Total daily capacity is that usable per-account figure multiplied by the number of SMTP accounts.
Per-account capacity = MIN(daily limit, active seconds ÷ delay)Total capacity = per-account capacity × SMTP accountsCampaign days = CEILING(list size ÷ total daily capacity)SMTP provider policies, domain reputation, bounce rates, complaint rates and inbox placement can reduce the volume you should actually send. Use this calculator for capacity planning, then validate the setup with the other WPMailDesk free tools.